Εμφάνιση ενός μόνο μηνύματος
  #3  
Παλιά 18-04-08, 21:56
Το avatar του χρήστη Σώτος Χριστοδούλου
Σώτος Χριστοδούλου Σώτος Χριστοδούλου is offline
 
Εγγραφή: 05-06-2007
Περιοχή: Κύπρος
Μηνύματα: 630
Απάντηση: Ζύγισμα Νατρασβέστου

Γιώργο γίνονται δύο υποθέσεις:

1. Δεν εισέρχεται ποσότητα υγρασίας στο κάνιστρο από leaks ή από την συμπύκνωση της εκπνοής, ή αν εισέρχεται είναι αμελητέα η ποσότητά της.

2. Όση υγρασία παράγεται από την χημική αντίδραση παραμένει μέσα στο κάνιστρο προσροφημένη πάνω στα κοκκίά ή συμπυκνωμένη (υγροποιημένη).

Στη συνέχεια έκανα μια δοκιμάστική μέτρηση (ζύγισμα δηλαδή για να ελέγξω πόσο κοντά στην υπόθεση βρίσκεται το πειραματικό εύρημα. Τα αποτελέσματα τα έχω δημοσιεύσει και στο RW. Αύριο πάμε για δεύτερη ομαδική μέτρηση και ελπίζω να έχουμε περισσότερα. Χωρίς εκτεταμένη διερεύνηση και πολλά δεδομένα δεν μπορεί για την ώρα να εξαχθεί κανένα συμπέρασμα παρα μόνο έχω πειστεί ότι αξίζει τον κόπο έστω από περιέργεια να κάνουμε κάποιες δοκιμές.

Χρησιμοποιώ το copy / paste πιο κάτω:

Η υπόθεση:

Sofnolime contains more than 70% of its weight in Ca(OH)2.

Therefore for a 2,5 Kg sorb (axial scrubber of Meg) there is more than 1750g of Ca(OH)2.

The mole of Ca(OH)2 is 74g. So we have in the scrubber 23 moles of Ca(OH)2.

Each mole of Ca(OH)2 can neutralise 1 mole of CO2. Since the mole of CO2 is 44g, theoretically we would expect that 23 X 44g of CO2 would be added to to weight of the scrubber if the efficiency of the scrubber is 100% (taking into account only the Ca(OH)2 which is the predominating base).

That is approximately 1 Kg of CO2.

Let's suppose that on average a diver produces 0,9 litres (1,77g) of CO2 per minute.

Theoretically again the scrubber would be good for 570 minutes under these CO2 production rates.

However since the scrubber is in the form of pellets one would expect that its efficiency is not 100%. ISC clearly states that the scrubber is good for 3,5 hours. We then assumpt that the scrubber efficiency is 210 minutes divided by 570 minutes (approximately 35%).

With 35% efficiency i would expect that 35% of 1Kg of CO2 could be neutralised in the Meg's axial scrubber. The is approximately 365g.

I would therefore assumpt that at the end of the scrubber life it will weight 365g more compare to its initial weight.

Assumption #1: All the water that is being produced inside the scrubber remains inside the scrubber

Assumption #2: No water from other sources is entering the scrubber.

Please note that the above are just assumptions and need to be modified according to actual findings from real experiments.

proposal: Check the scrubber weight after 3,5 hours of use at more or the less oxygen consumption of 1 LPM and compare it with the calculated expected weight increase of 14,5%. (365g over 2500 g).

Το ζύγισμα:

Further to the above hypothesis today I did my first weighing. Not all parameters were measured as this was a preliminary experiment to check if the hypothesis is anywhere close to correct. Apparently the results are encouranging and I am planning to continue this experiement in a proper and standardised protocol.

Todays Measurements:

TOTAL DIVE TIME: 182 minutes (3 dives).

INITIAL WEIGHT: 2500 g

FINAL WEIGHT 25 minutes after opening the canister: 2835 g

FINAL WEIGHT 3 hours after opening the canister: 2830 g.

WEIGHT CHANGE EXPECTED: 316 g MEASURED: 330 - 335 g

The initial hypotheis was that a Meg scrubber would have an increase of 365 g after 3,5 hours of use (or 14,5% weight increase given the 2,5 Kg initial weigh). Given the analogies one would expect a weight increase of 316 g after 182 minutes of use. Of course there will always be a deviation as not all dives are of the same activity level. My dives where relaxed and the activity level minimal. These findings are anyhow, in line with the above hypothesis and therefore the whole issue requires further investigation. Gathering and analysing more data would be ideal, so anyone who has the extra time may please contribute to this? IMHO it worths a try.

P.S. For those who want to contribute please see the attached excel file for data recording.
Απάντηση με παράθεση